Device with pillar-shaped components

ABSTRACT

A device with pillar-shaped components, includes a substrate; a wiring layer disposed on the substrate; and pillar-shaped components disposed on any of the substrate and the wiring layer, each of the pillar-shaped components having a bottom part connected to the substrate and/or the wiring layer, a top part opposed to the bottom part, and a lateral face part extending from the bottom part and connected to the top part; wherein each of the pillar-shaped components includes a first pillar-shaped part formed by plating, a second pillar-shaped part formed on the first pillar-shaped part by plating, and a ring-like projection part formed on the lateral face part to project outward and extend in a circumferential direction, and to be in a position higher than a joint position between the first pillar-shaped part and the second pillar-shaped part.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of application Ser. No.13/861,073 filed on Apr. 11, 2013, now U.S Pat. No. 9,283,402 issued onMar. 22, 2016, which claims priority under 35 USC 119 to Japanese PatentApplication No. 2012-091952 filed on Apr. 13, 2012 Japanese PatentApplication No. 2012-0191951 filed on Apr. 13, 2012, Japanese PatentApplication No. 2012-091953 filed on Apr. 13, 2012, the disclosures ofwhich are incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a device with pillar-shaped components,and in particular, relates to an electronic device with pillar-shapedcomponents.

2. Description of the Related Art

Recently, electronic devices such as cellular phones and digital camerashave been downsized, and therefore smaller semiconductor devices havebeen highly demanded for being mounted in such electronic devices. Tomeet such a demand, a wafer-level chip size packaging technology forforming a wafer-level chip size package (WL-CSP) has been developed. TheWL-CSP is formed as a small package of the same size as a chip size.Furthermore, development of WL-CSPs each having an additional componentmounted in a sealing resin has been also promoted.

For example, Japanese Patent Application Publication No. 2002-299496(Patent Document 1) discloses a semiconductor device manufacturingmethod including a step of forming a post electrode composed of a stackof two copper (Cu) layers and a step of mounting a capacitor as anadditional component sealed in a sealing resin. According to the methodof Patent Document 1, as illustrated in a flowchart of FIG. 1, a postelectrode is formed by the following steps (A) to (C):

A first Cu layer forming step including: forming a first resist film ona conductive film disposed on a semiconductor wafer (step S101); forminga hole by light-exposure and development (steps S102 and S103); formingthe first Cu layer by plating (step S104); removing the first resistfilm (step S105); forming a temporary seal layer on the first Cu layer(step S106); and applying CMP to the first Cu layer and the temporaryseal layer (step S107).

(B) A second Cu layer forming step including: forming a second resistfilm (step S 108); forming a hole by light-exposure and development(steps S109 and S110); forming the second Cu layer by plating (stepS111); removing the second resist film (step S112); forming a temporaryseal layer on the second Cu layer (step S113); and applying CMP to thesecond Cu layer and the temporary seal layer (step S114).

(C) An electronic component mounting step including: removing thetemporary seal layers (step S115); mounting a capacitor as an electroniccomponent (step S116); forming an insulation layer (step S117); applyingCMP to the capacitor and the insulation layer (step S118); and formingan electrode and a solder bump (step S119).

Furthermore, Japanese Patent Application Publication No. 2004-172163(Patent Document 2) discloses a multilayered structure including a lowerpost electrode part (first post electrode part) and an upper postelectrode part (second post electrode part) disposed on the lower postelectrode part.

In the semiconductor device of Patent Document 1, a boundary positionbetween the temporary seal layers as the first and second layerscorresponds with a joint position between the first Cu layer and thesecond Cu layer. At the boundary position between the temporary seallayer as the first layer and the second temporary seal layer as thesecond layer, an undesirable ring-like projection part disposed at theboundary position between the temporary seal layers and extending in acircumferential direction is frequently formed on a lateral face part ofthe Cu post electrode composed of the first and second Cu layers.

Furthermore, in the semiconductor device of Patent Document 2, since acircumferential length of the second post electrode part is shorter thana circumferential length of the first post electrode part, a step (or astep-like part) is formed at a joint position between the first andsecond post electrode parts.

As described above, if a post electrode has a projection part or astep-like part disposed at the joint position between the layers (postelectrode parts) made of copper whose mechanical strength iscomparatively low, the projection part or the step-like part issubjected to internal stress caused by a substrate warpage ordeformation. Therefore, the devices of Patent Documents 1 and 2 have aproblem of a high frequency of occurrence of defective post electrodes,in which the post electrodes are fallen out or broken.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a device withpillar-shaped components disposed on a substrate with less frequency ofoccurrence of defective pillar-shaped components.

According to an aspect of the present invention, a device withpillar-shaped components, includes a substrate; a wiring layer disposedon the substrate; and pillar-shaped components disposed on any of thesubstrate and the wiring layer, each of the pillar-shaped componentshaving a bottom part connected to any of the substrate and the wiringlayer, a top part opposed to the bottom part, and a lateral face partextending from the bottom part to the top part to connect the bottompart and the top part. Each of the pillar-shaped components includes afirst pillar-shaped part formed by plating, a second pillar-shaped partformed on the first pillar-shaped part by plating, and a ring-likeprojection part formed on the lateral face part to project outward andextend in a circumferential direction, the ring-like projection partbeing formed in a position higher than a joint position between thefirst pillar-shaped part and the second pillar-shaped part.

According to the present invention, a frequency of occurrence ofdefective pillar-shaped components in a device with pillar-shapedcomponents is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus are not limitativeof the present invention, and wherein:

FIG. 1 is a flowchart illustrating a conventional post electrode formingmethod;

FIG. 2 is a flowchart illustrating a method of manufacturing asemiconductor device in a comparison example;

FIGS. 3A to 3I are schematic sectional views illustrating processes ofthe method of manufacturing the semiconductor device in the comparisonexample;

FIGS. 4A to 4D are schematic sectional views illustrating processes ofthe method of manufacturing the semiconductor device in the comparisonexample;

FIG. 5 is a schematic sectional view illustrating a semiconductor deviceas a device with pillar-shaped components in the comparison example;

FIG. 6 is a flowchart illustrating a method of manufacturing a devicewith pillar-shaped components according to a first embodiment of thepresent invention;

FIGS. 7A to 7E are schematic sectional views illustrating processes ofthe method of manufacturing a device with pillar-shaped componentsaccording to the first embodiment;

FIGS. 8A to 8D are schematic sectional views illustrating processes ofthe method of manufacturing the device with pillar-shaped componentsaccording to the first embodiment;

FIGS. 9A to 9C are schematic sectional views illustrating processes ofthe method of manufacturing the device with pillar-shaped componentsaccording to the first embodiment;

FIG. 10A is a diagram illustrating an aspect ratio in the comparisonexample;

FIGS. 10B and 10C are diagrams illustrating an aspect ratio in the firstembodiment;

FIG. 11A is a diagram illustrating a plating process in the comparisonexample;

FIGS. 11B and 11C are diagrams illustrating a plating process in thefirst embodiment;

FIG. 12 is a diagram illustrating a problem in the comparison example;

FIG. 13 is a schematic sectional view illustrating a pillar-shapedcomponent in the device with pillar-shaped components according to thefirst embodiment;

FIG. 14 is an enlarged view of an essential part in FIG. 13;

FIG. 15 is a flowchart illustrating a method of manufacturing a devicewith pillar-shaped components according to a second embodiment of thepresent invention;

FIGS. 16A to 16D are schematic sectional views illustrating processes ofthe method of manufacturing a device with pillar-shaped componentsaccording to the second embodiment;

FIGS. 17A to 17D are schematic sectional views illustrating processes ofthe method of manufacturing the device with pillar-shaped componentsaccording to the second embodiment;

FIGS. 18A and 18B are schematic sectional views illustrating processesof the method of manufacturing the device with pillar-shaped componentsaccording to the second embodiment;

FIG. 19 is a plan view schematically illustrating forming slits in themethod of manufacturing a device with pillar-shaped components accordingto the second embodiment;

FIG. 20 is a flowchart illustrating a modified example of the method ofmanufacturing a device with pillar-shaped components according to thesecond embodiment;

FIGS. 21A to 21E are schematic sectional views illustrating processes ofthe modified example of the method of manufacturing the device withpillar-shaped components according to the second embodiment;

FIGS. 22A to 22D are schematic sectional views illustrating processes ofthe modified example of the method of manufacturing the device withpillar-shaped components according to the second embodiment;

FIG. 22E illustrates another example of FIG. 22D;

FIGS. 23A to 23D are schematic sectional views illustrating processes ofthe modified example of the method of manufacturing a device withpillar-shaped components according to the second embodiment;

FIG. 24 is a side view schematically illustrating a warpage of asemiconductor wafer which may be caused when two dry films are attachedin layers to the semiconductor wafer;

FIG. 25 is a side view schematically illustrating dry film detachmentwhich may be caused when the two dry films are attached in layers to thesemiconductor wafer;

FIG. 26 is a side view schematically illustrating an undesired Cuelectrode formed in a gap between the dry film and the wafer in aplating process when the dry film detachment is caused;

FIG. 27A is a diagram illustrating a normal plating process; and

FIG. 27B is a diagram illustrating an undesired state where a piece ofthe dry film covers a hole.

DETAILED DESCRIPTION OF THE INVENTION

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications will become apparent to those skilled in the art from thedetailed description.

A device according to the present invention includes a substrate; awiring layer disposed on the substrate; and pillar-shaped componentsdisposed on any of the substrate and the wiring layer. Each of thepillar-shaped components has a bottom part connected to any of thesubstrate and the wiring layer, a top part opposed to the bottom part,and a lateral face part extending from the bottom part to the top partto connect the bottom part and the top part. Furthermore, each of thepillar-shaped components includes a first pillar-shaped part formed byplating, a second pillar-shaped part formed on the first pillar-shapedpart by plating, and a ring-like projection part formed on the lateralface part to project outward and extend in a circumferential direction,the ring-like projection part being formed in a position higher than ajoint position between the first pillar-shaped part and the secondpillar-shaped part.

The device may include an additional component formed on any of thesubstrate and the wiring layer so as to be mounted outside an area wherethe pillar-shaped components are disposed.

The pillar-shaped components disposed on the wiring layer are postelectrodes. On the other hand, the pillar-shaped components disposed onthe substrate may be pillar-shaped metal components for radiating heat.

Detailed descriptions will be made as to cases where a device withpillar-shaped components is a semiconductor device with post electrodes.However, the present invention may be applied to a device other than thesemiconductor device or a device with pillar-shaped components otherthan the post electrodes.

First, a comparison example which is used for explaining the first andsecond embodiments of the present invention will be described, and thenthe first and second embodiments will be described. The comparisonexample and the first and second embodiments relate to a device withpillar-shaped components such as post electrodes that are formed so asto penetrate a molding resin as a sealing resin in a thickness directionwhen an additional component such as an electronic component is mountedon a re-distribution wiring layer disposed on a substrate and sealedwith the molding resin in a WL-CSP, and also relates to a method offorming pillar-shaped components such as post electrodes.

<<1>> Comparison Example

FIG. 2 is a flowchart illustrating a method of manufacturing a devicewith pillar-shaped components in the comparison example. FIGS. 3A to 3Iare schematic sectional views illustrating processes of the method ofmanufacturing the device with pillar-shaped components in the comparisonexample, and FIGS. 4A to 4D are schematic sectional views illustratingprocesses of the method of manufacturing the device with pillar-shapedcomponents in the comparison example. The process illustrated in FIG. 4Ais a process subsequent to the process illustrated in FIG. 3I.Furthermore, FIG. 5 is a schematic sectional view illustrating thedevice with pillar-shaped components in the comparison example. Themethod of manufacturing the device with pillar-shaped components in thecomparison example will be described below, by referring to thedrawings.

FIG. 3A illustrates a semiconductor wafer which is obtained after awafer process including an impurity diffusion process is finished. InFIG. 3A, a wiring layer 102 and an interlayer dielectric film 103 areformed on the semiconductor wafer 101, a via (i.e., a via contactstructure) 104 connected to the wiring layer 102 is formed in theinterlayer dielectric film 103, and a wiring layer 105 connected to thevia 104 and a passivation film 106 coating the interlayer dielectricfilm 103 are formed.

Next, as illustrated in FIG. 3B, a lower dielectric film 107 is formedon the passivation film 106, and then an opening is formed in the lowerdielectric film 107 so as to correspond to an opening on the passivationfilm 106.

Next, as illustrated in FIG. 3C, an under barrier metal (UBM) film 108is formed on the entire surface of the wafer. Then, a resist film (notillustrated in the drawings) is formed on the entire surface of thewafer and a pattern of openings is formed in the resist film for forminga re-distribution wiring layer 109 by using lithographic techniques. There-distribution wiring layer 109 is formed by plating only on an areawithout the resist film. Thereafter, the resist film is removed by anashing process.

Next, as illustrated in FIG. 3D, a first photoresist dry film 110 isattached to the entire surface of the wafer on which the re-distributionwiring layer 109 is formed (step S201 in FIG. 2), and then a secondphotoresist dry film 111 is attached to an upper surface of the firstphotoresist dry film 110 (step S202 in FIG. 2). In the followingexplanation, the photoresist dry film will be also referred to as ‘dryfilm’. Furthermore, a thickness of the dry film 110 is 120 μm, forexample.

Next, as illustrated in FIG. 3E, light-exposure and developmentprocesses are carried out by using lithographic techniques to formopenings (i.e., holes) 112 on the re-distribution wiring layer 109 sothat the openings 112 penetrate the first and second dry films 110 andfilm 111 in a thickness direction of the first and second dry films 110and 111 (steps S203 and S204 in FIG. 2).

Next, as illustrated in FIG. 3F, post electrodes 113 as pillar-shapedcomponents made of copper is formed in the openings 112 by plating suchas electroplating. In FIG. 3, the post electrodes 113 are formed only inthe openings 112 formed in the dry film (step S205 in FIG. 2).

Next, as illustrated in FIG. 3G, the second and first dry films 111 and110 are removed by carrying out chemical liquid treatment, and then theUBM film 108 is partially removed while the re-distribution wiring layer109 functions as a stopper film (step S206 in FIG. 2).

Next, as illustrated in FIG. 3H, an additional component 114 is mountedon the re-distribution wiring layer 109 (step S207 in FIG. 2). Theadditional component 114 is an electronic component such as alight-emitting device, a light-receiving device, or other devices. Thereare no restrictions on the kind and the number of the additionalcomponents 114.

Then, as illustrated in FIG. 3I and FIG. 4A, the entire surface of thewafer is sealed with a molding resin 115 (step S208 in FIG. 2).

Next, as illustrated in FIG. 4B, a Si wafer 120 resultant from thesealing with the molding resin 115 is ground by using a CMP method sothat top parts of the post electrodes 113 are exposed (step S209 in FIG.2). At this time, the post electrodes 113 are formed so that each of thetop parts of the post electrodes 113 is higher than a top part of theadditional component 114. A height of each of the post electrodes 113can be increased by increasing the number of dry films of a multilayeredstructure of photoresist dry films (i.e., multilayered dry filmstructure).

Then, as illustrated in FIG. 4C, a solder mask 116 is disposed and asolder paste 117 is printed on the post electrode 113. As illustrated inFIG. 4D, the solder mask 116 is removed, and then a reflow process iscarried out so that hemisphere-shaped solder terminals 118 are formed(step S210 in FIG. 2).

The WL-CSP device with pillar-shaped components in which the additionalcomponent is mounted on the re-distribution wiring layer and sealed withthe molding resin is thus manufactured by the above-described processes,and the WL-CSP illustrated in FIG. 5 has been completed.

<<2>> First Embodiment

<<2-1>> Manufacturing Method

FIG. 6 is a flowchart illustrating a method of manufacturing a devicewith pillar-shaped components according to the first embodiment. FIGS.7A to 7E are schematic sectional views illustrating processes of themethod of manufacturing the device with pillar-shaped componentsaccording to the first embodiment, FIGS. 8A to 8D are schematicsectional views illustrating processes of the method of manufacturingthe device with pillar-shaped components according to the firstembodiment, and FIGS. 9A to 9C are schematic sectional viewsillustrating processes of the method of manufacturing the device withpillar-shaped components according to the first embodiment. The processillustrated in FIG. 8A is a process subsequent to the processillustrated in FIG. 7E, and the process illustrated in FIG. 9A is aprocess subsequent to the process illustrated in FIG. 8D. Furthermore,FIGS. 10A to 10C are schematic sectional views illustrating aspectratios, and FIGS. 11A to 11C are diagrams illustrating plating processesin structures illustrated in FIGS. 10A to 10C.

FIG. 7A illustrates a semiconductor wafer which is obtained after awafer process including an impurity diffusion process and otherprocesses is finished. In FIG. 7A, the wiring layer 102 and theinterlayer dielectric film 103 are formed on the semiconductor wafer 101(e.g., see semiconductor wafer 101 shown in FIG. 3A), the via 104 (i.e.,via contact structure) connected to the wiring layer 102 is formed inthe interlayer dielectric film 103, and the wiring layer 105 connectedto the via 104 and the passivation film 106 coating the interlayerdielectric film 103 are formed.

Next, as illustrated in FIG. 7B, the lower dielectric film 107 isformed, and then an opening is formed in the lower dielectric film 107so as to correspond to an opening in the passivation film 106.

Next, as illustrated in FIG. 7C, the UBM film 108 is formed on theentire surface of the wafer. Then, a resist film (not illustrated in thedrawing) is formed on the entire surface of the wafer and a pattern ofopenings is formed in the resist film for forming a re-distributionwiring layer 109 by using lithographic techniques. The re-distributionwiring layer 109 is formed by plating such as electroplating only in theopenings of the resist film (i.e., on areas without the resist film),and then the resist film is removed by an ashing process.

Next, as illustrated in FIG. 7D, a first dry film 210 is attached to theentire surface of the wafer on which the re-distribution wiring layer109 is formed (step Si in FIG. 6).

Next, as illustrated in FIG. 7E, openings (i.e., holes) 212 a are formedin the re-distribution wiring layer 109 by using lithographic techniquesso that the openings 212 a penetrate the first dry film 210 in athickness direction of the first dry film 210 (steps S2 and S3 in FIG.6).

Next, as illustrated in FIG. 8A, first post electrode parts 213 a asfirst pillar-shaped parts are formed by plating such as electroplating(step S4 in FIG. 6). Copper (Cu) electrodes are usually used as thefirst post electrode parts 213 a. However, another metal such as gold orpalladium may be also used as the first post electrode parts 213 a. Atthis time, the first post electrode parts 213 a are formed only in theopening 212 a of the first dry film 210. As illustrated in FIG. 8A, thefirst post electrode parts 213 a are formed so that upper surfaces ofthe first post electrode parts 213 a are lower than an upper surface 210a of the first dry film 210.

Next, as illustrated in FIG. 8B, a second dry film 211 is attached tothe entire surface of the wafer (step S5 in FIG. 6).

Next, as illustrated in FIG. 8C, openings (i.e., holes) 212 b are formedin the second dry film 211 over the openings 212 a of the first dry film210 by using lithographic techniques so that the openings 212 bcorrespond with the openings 212 a (steps S6 and S7 in FIG. 6)respectively. The openings 212 b penetrate the second dry film 211 in athickness direction of the second dry film 211.

Next, as illustrated in FIG. 8D, second post electrode parts 213 b assecond pillar-shaped parts are formed on the first post electrode parts213 a respectively by plating such as electroplating (step S8 in FIG.6). A copper (Cu) electrode is usually used as the second post electrodeparts 213 b. However, another metal such as gold or palladium may bealso used as the second post electrode parts 213 b. At this time, thesecond post electrode parts 213 b are formed only in the openings 212 bof the second dry film 211. It is desirable that the second postelectrode parts 213 b should be formed to be higher than an uppersurface of the second dry film 211. If a plurality of second postelectrode parts 213 b is formed on a semiconductor wafer, a platingspeed in a center part and a plating speed in a peripheral part on thesemiconductor wafer are sometimes different from each other. To copewith this case, all of the second post electrode parts are formed sothat all of them are higher than the upper surface of the second dryfilm 211. Multilayered structures of the first and second post electrodeparts 213 a and 213 b are also referred to as post electrodes 213 aspillar-shaped components.

In a case where multilayered structures of three or more dry films areused, it is desirable that upper surfaces of the second post electrodeparts 213 b should be formed to be lower than the upper surface of thesecond dry film, in a similar manner to the upper surfaces of the firstpost electrode parts 213 a.

Next, as illustrated in FIG. 9A, the second and first dry films 211 and210 are removed by carrying out chemical liquid treatment (step S9 inFIG. 6), and then the UBM film 108 is partially removed while there-distribution wiring layer 109 functions as a stopper film.

Next, as illustrated in FIG. 9B, an additional component 214 is mountedon the re-distribution wiring layer 109 (step S10 in FIG. 6). Forexample, the additional component 214 is a chip or a packaged electroniccomponent such as a light-emitting device, a light-receiving device, anoscillation device, a sensor electronic component, or other components.There are no restrictions on the kind or the number of the additionalcomponents 214.

Then, as illustrated in FIG. 9C, the entire surface of the wafer issealed with a molding resin 215 as a sealing resin (step S11 in FIG. 6).Then, the processes as illustrated in FIGS. 3A to 3D are carried out(steps S12 and S13 in FIG. 6). The WL-CSP device with pillar-shapedcomponents in which the additional component 214 is mounted on there-distribution wiring layer 109 or the substrate and sealed with themolding resin 215 is thus manufactured by the above-described processes.

<<2-2>> Effects of First Embodiment

FIG. 10A illustrates an aspect ratio of a hole, i.e., a ratio of a depthto a width of the hole, in the comparison example; and FIGS. 10B and 10Cillustrate an aspect ratio of a hole in the first embodiment. In thefirst embodiment, the first dry film 210 is used as a mask for formingthe first post electrode parts 213 a by plating, the second dry film 211is used as a mask for forming the second post electrode parts 213 bafter the first post electrode parts 213 a are formed, and thus the postelectrodes 213 of sufficient height are formed. Thus, by performing theprocess for forming the post electrode parts a plurality of times (twicein this case), an aspect ratio of the hole of the dry film can bereduced in the post electrode forming process, in comparison with thecomparison example illustrated in FIG. 10A.

As illustrated in FIG. 11A, if a hole (i.e., opening) of the dry filmhas a high aspect ratio, it is extremely difficult to remove air bubblesin the plating solution that remain in the opening when a cup-typeplating apparatus without a deaerator for removing air bubbles in theplating solution is used for plating. The air bubbles remaining in theopening of the dry films 110 and 111 interferes with copper plating. Inaddition, if the plating is carried out for forming the post electrodeswhile a plating solution includes air bubbles, the resultant postelectrodes 113 include defective hollow parts (i.e., empty spaces)inside as illustrated in FIG. 12. The hollow parts in the post electrode113 seriously damage strength and reliability of the post electrodes 113and cause a breakage of the post electrodes in the manufacturingprocesses or a defective product on the market.

According to the method in the first embodiment, even if an inexpensiveplating apparatus such as a plating apparatus without a deaerator or acup-type plating apparatus is used, air bubbles are easy to exit through(i.e., be removed from) the openings, as illustrated in FIGS. 11B and11C. Therefore, the post electrodes (213 in FIG. 9C) are formed so theupper surfaces of the post electrodes are higher than the mountedadditional component 214 without the problem of occurrence of defectivehollow parts in the post electrodes 213.

Moreover, since the first post electrode parts 213 a are formed so thatthe upper surfaces of the first post electrode parts 213 a are lowerthan the upper surface of the first dry film 210 while the first dryfilm 210 is used as a mask, the post electrodes 213 can be preventedfrom falling out and weak adhesion when the second dry film 211 isattached to the first dry film 210 can be prevented.

Furthermore, top parts of the openings of the pattern of the first dryfilm 210 tend to be enlarged as a result of the developing process ofthe pattern of the first dry film 210. Accordingly, each of the postelectrodes 213 has a projection part 240 slightly projecting toward theopening near an interface between the first dry film 210 and the seconddry film 211. The projection part 240 can prevent the post electrode 213from falling out from the molding resin 215.

As described above, in the first embodiment, the post electrodes 213 ofa sufficient height are formed by performing each of the processes ofdry film attaching and the post electrode parts forming by platingtwice. Therefore, even if a simple and inexpensive plating apparatus isused, the post electrodes of a sufficient height for mounting anadditional component can be obtained without defective hollow parts(i.e., empty spaces) inside the post electrodes 213.

FIG. 13 is a schematic sectional view illustrating the post electrode213 in the device with pillar-shaped components according to the firstembodiment. FIG. 14 is an enlarged perspective view of an essential part‘A’ in FIG. 13. As illustrated in FIG. 13, the pillar-shaped postelectrode 213 includes a bottom part connected to the re-distributionlayer 109 disposed on the semiconductor wafer, a top part being opposedto the bottom part, and a lateral face part joining the bottom part andthe top part. In the first embodiment, a joint position 230 between thefirst post electrode part 213 a and the second post electrode part 213 bis lower than the interface between the first and second dry films 210and 211. Near the interface between the first and second dry films 210and 211, a ring-like projection part (step-like part) 240 is formed. Thering-like projection part projects outward and extends in acircumferential direction as illustrated in FIG. 14. Such a structurecan prevent the problem of weak adhesion when the second dry film 211 isattached to the first dry film 210. Furthermore, the ring-likeprojection part 240 at the interface between the first and second dryfilms 210 and 211 can prevent the post electrode from falling out fromthe molding resin.

In addition, if third post electrode parts are formed on the second postelectrode parts by using a third photoresist dry film (not illustratedin the drawings) which is layered on the second photoresist dry film211, it is desirable to form a structure of the second and third postelectrode parts that has a structure similar to that of the first andsecond post electrode parts 213 a and 213 b as illustrated in FIGS. 13and 14.

<<3>> Second Embodiment

<<3-1>> Manufacturing Method

FIG. 15 is a flowchart illustrating a method of manufacturing a devicewith pillar-shaped components according to the second embodiment. FIGS.16A to 16D are schematic sectional views illustrating processes of themethod of manufacturing the device with pillar-shaped componentsaccording to the second embodiment, FIGS. 17A to 17D are schematicsectional views illustrating processes of the method of manufacturingthe device with pillar-shaped components according to the secondembodiment, and FIGS. 18A and 18B are schematic sectional viewsillustrating processes of the method of manufacturing the device withpillar-shaped components according to the second embodiment. FIG. 17Aillustrates the process subsequent to the process illustrated in FIG.16D, and FIG. 18A illustrates the process subsequent to the processillustrated in FIG. 17D. In each of FIGS. 16A to 16D, FIGS. 17A to 17Dand FIGS. 18A and 18B, a region in a center part (excluding an outercircumferential part) of a wafer is illustrated on the left and a regionnear the outer circumferential part of the wafer is illustrated on theright. Furthermore, FIG. 19 is a plan view schematically illustrating anexample of forming slits.

FIG. 16A illustrates a wafer fabricated by the same processes as theprocesses described in the first embodiment illustrated by referring toFIGS. 7A to 7C.

Next, as illustrated in FIG. 16B, a first dry film 310 is attached tothe entire surface of the wafer on which the re-distribution wiringlayer 109 is formed (step Si in FIG. 15).

Next, as illustrated in FIG. 16C, openings (i.e., holes) 312 a areformed in the re-distribution wiring layer 109 by using lithographictechniques (steps S2 and S3 in FIG. 15). The openings 312 a penetratethe first dry film 310 in a thickness direction of the first dry film310.

Next, as illustrated in FIG. 16D, first post electrode parts 313 a asfirst pillar-shaped parts are formed by plating such as electroplating(step S4 in FIG. 15). At this time, the first post electrode parts 313 aare formed only in the openings 312 a in the first dry film 310 (step S4in FIG. 15). The first post electrode parts 313 a are formed so thattheir upper surfaces are lower than an upper surface 310 a of the firstdry film 310.

Next, as illustrated in FIG. 17A, a second dry film 311 is attached tothe entire surface of the wafer (step S5 in FIG. 15).

Next, as illustrated in FIG. 17B, openings (i.e., holes) 312 b areformed over the openings 312 a of the first dry film 310 and slits 320are formed as long grooves on the second dry film 311 by usinglithographic techniques (steps S21 and S22 in FIG. 15). The openings 312b penetrate the second dry film 311 in a thickness direction of thesecond dry film 311. FIG. 19 illustrates an example of the slits 320. Asillustrated in FIG. 19, the slits 320 may be arranged in a grid patternor in grid-like fashion so that each of square regions surrounded byneighboring slits 320 includes a predetermined number of postelectrodes, i.e., one or more post electrodes. An object of forming theslits 320 is to avoid problems, such as a wafer warpage or deformation,caused by internal stress that arises due to shrinkage of the dry filmwhen the dry films are attached in layers to the semiconductor wafer.The arrangement of the slits 320 is not limited to the example shown inFIG. 19.

Next, as illustrated in FIG. 17C, second post electrode parts 313 b assecond pillar-shaped parts are formed on the first post electrode parts313 a respectively by plating such as electroplating (step S8 in FIG.15). At this time, the second post electrode parts 313 b are formed inthe openings of the second dry film 311. It is desirable that uppersurfaces of the second post electrode parts 313 b should be higher thanan upper surface of the second dry film 311.

Next, as illustrated in FIG. 17D, the second and first dry films 311 and310 are removed by carrying out chemical liquid treatment (step S9 inFIG. 15), and then the UBM film 108 is removed while the re-distributionwiring layer 109 functions as a stopper film.

Next, as illustrated in FIG. 18A, an additional component 314 is mountedon the re-distribution wiring layer 109 (step S10 in FIG. 15) or on thesubstrate.

Thereafter, as illustrated in FIG. 18B, the entire surface of the waferis sealed with a molding resin 315 such as a sealing resin (step S11 inFIG. 15). Then, the processes as illustrated in FIGS. 3A to 3D arecarried out (steps S12 and S13 in FIG. 6). The WL-CSP device withpillar-shaped components in which the additional component is mounted onthe re-distribution wiring layer and sealed with the molding resin isthus manufactured by the above-described processes.

<<3-2>> Modified Example of Second Embodiment

FIG. 20 is a flowchart illustrating a modified example of the method ofmanufacturing the device with pillar-shaped components according to thesecond embodiment. FIGS. 21A to 21E are schematic sectional viewsillustrating processes of the modified example of the method ofmanufacturing the device with pillar-shaped components according to thesecond embodiment, FIGS. 22A to 22E are schematic sectional viewsillustrating processes of the modified example of the method ofmanufacturing the device with pillar-shaped components according to thesecond embodiment, and FIGS. 23A to 23D are schematic sectional viewsillustrating processes of the modified example of the method ofmanufacturing the device with pillar-shaped components according to thesecond embodiment. FIG. 22A illustrates the process subsequent to theprocess illustrated in FIG. 21E, and FIG. 23A illustrates the processsubsequent to the process illustrated in FIG. 22D. In each of FIGS. 21Ato 21E, FIGS. 22A to 22E, and FIGS. 23A to 23D, a region in a centerpart (excluding an outer circumferential part) of a wafer is illustratedon the left and a region near the outer circumferential part of thewafer is illustrated on the right.

FIG. 21A illustrates a wafer fabricated by the same processes as theprocesses in the first embodiment illustrated in FIGS. 7A to 7C.

Next, as illustrated in FIG. 21B, a first dry film 410 is attached tothe entire surface of the wafer on which the re-distribution wiringlayer 109 is formed (step Si in FIG. 20).

Next, as illustrated in FIG. 21C, openings (i.e., holes) 412 a areformed in the re-distribution wiring layer 109 and slits 420 are formedas long grooves on the first dry film 410 by using lithographictechniques. The openings 412 a penetrate the first dry film 410 in athickness direction of the first dry film 410. In the outercircumferential part of the wafer, a resist removal part is formed(steps S31 and S32 in FIG. 20).

Next, as illustrated in FIG. 21D, a resist 421 is applied on the entiresurface of the wafer. Then, as illustrated in FIG. 21E, the resist 421is removed from the openings 412 a by patterning process for formingpost electrodes in the openings 412 a (step S33 in FIG. 20).

Next, as illustrated in FIG. 22A, first post electrode parts 413 a asfirst pillar-shaped parts are formed by plating such as electroplating.At this time, the first post electrode parts 413 a are formed in theopenings of the first dry film 410 (step S4 in FIG. 20).

Next, as illustrated in FIG. 22B, the resist 421 is removed from theouter circumferential part of the wafer. Then, as illustrated in FIG.22C, a second dry film 411 is attached to the first dry film 410 (stepS5 in FIG. 20). At this time, in the outer circumferential part of thewafer, the second dry film 411 is also attached to a region from whichthe first dry film 410 is removed, i.e., the second dry film 411 is alsoattached to the UBM film.

Next, as illustrated in FIG. 22D, openings (i.e., holes) 412 b areformed over the openings 412 a of the first dry film 410 and openings422 is formed over the slits 420 (steps S34 and S35 in FIG. 20) by usinglithographic techniques. The openings 412 b penetrate the second dryfilm 411 in a thickness direction of the second dry film 411. The seconddry film may be formed as illustrated in FIG. 22E instead of FIG. 22D.It means that only the openings 412 b may be formed over the openings412 a of the first dry film 410 by using lithographic techniques so asto penetrate the second dry film 411 in the thickness direction.

Next, as illustrated in FIG. 23A, second post electrode parts 413 b assecond pillar-shaped parts are formed on the first post electrode parts413 a respectively by plating such as electroplating (step S8 in FIG.20). At this time, the second post electrode parts 413 b are formed inthe openings 412 b of the second dry film 411. It is desirable thatupper surfaces of the second post electrode parts 413 b should be higherthan an upper surface of the second dry film 411.

Next, as illustrated in FIG. 23B, the second and first dry films 411 and410 are removed by carrying out chemical liquid treatment, and then theUBM film 108 is removed while the re-distribution wiring layer 109functions as a stopper film (step S9 in FIG. 20).

Next, as illustrated in FIG. 23C, an additional component 414 is mountedon the re-distribution wiring layer 109 (step S10 in FIG. 20).

Then, as illustrated in FIG. 23D, the entire surface of the wafer issealed with a molding resin 415 (step S11 in FIG. 20). Then, theprocesses as illustrated in FIGS. 3A to 3D are carried out (steps S12and S13 in FIG. 20). The WL-CSP device with pillar-shaped components inwhich an additional component is mounted on the re-distribution wiringlayer or on the substrate and sealed with the molding resin is thusmanufactured by these processes.

<<3-3>> Effects of Second Embodiment

FIG. 24 is a side view schematically illustrating a warpage ordeformation of a semiconductor wafer which may be caused when two dryfilms are attached in layers to the semiconductor wafer. FIG. 25 is aside view schematically illustrating dry film detachment which may becaused when the two dry films are attached in layers to thesemiconductor wafer. FIG. 26 is a side view schematically illustratingan undesired Cu electrode which is formed in a gap between the dry filmand the wafer in a plating process when the dry film detachment iscaused. FIG. 27A is a diagram illustrating a normal plating process; andFIG. 27B is a diagram illustrating an undesired state where a piece ofthe dry film covers a hole.

For example, as illustrated in FIG. 3D, in a case where the postelectrode of a sufficient height for mounting the additional componentis formed by using the thick dry films 110 and 111, considerableinternal stress in the dry films 110 and 111 in layers causes a waferwarpage. In addition, the internal stress concentrates at an end part ofthe dry films 110 and 111 (i.e., near a wafer edge part) and it mayresult in detachment of a part of the dry films 110 and 111 near thewafer edge part (i.e., near an outer circumferential part of the wafer)as illustrated in FIG. 25. The detachment of the dry films 110 and 111may cause the following problems. A detached piece of the dry film getsin a plating solution, an opening is undesirably covered by the pieceand plating is not normally grown, as illustrated in FIG. 27B. Moreover,an undesired post electrode (e.g. Cu electrode) may be grown in a gapbetween the wafer and the dry films 110 and 111 as illustrated in FIG.26, and the wafer may be broken from the undesired Cu electrode in aprocess after a post electrode is formed by plating. Furthermore, theinternal stress of the thick dry films 110 and 111 may cause a waferwarpage. Such a wafer warpage may cause an error in vacuum adsorption orthe like in the device after the dry film is attached and may cause aproblem in a workflow.

To cope with such problems, in the second embodiment, the postelectrodes are formed by using the two dry films in layers.Notwithstanding the internal stress of the thick dry film concentratesat a part of the outer circumferential part of the wafer, the internalstress can be distributed by removing a part of the second dry film inthe outer circumferential part. At this time, the outer circumferentialpart is covered by the first dry film and an undesired post electrodecan be prevented from growing in the outer circumferential part. Inaddition, by forming the slits in a grid pattern on the second dry film,the internal stress caused in the dry film can be distributed and awafer warpage amount of the entire wafer can be reduced. The warpagepreventing effect of the slits is effective when a total thickness ofthe first and second dry films 310 and 311 is 100 μtm or more,especially 150 μm or more.

Moreover, when a part of the first dry film in the outer circumferentialpart is removed, the second dry film is closely adhered to the UBM film108 in the outer circumferential part and covers an end surface of thefirst dry film. This can prevent the plating solution from soakingthrough the interface between the dry films, as well as reduce theinternal stress.

As described above, in the second embodiment, by removing a part of thedry film in the outer circumferential part, detachment of the dry filmdue to internal stress concentration can be prevented and a breakage ofthe wafer due to a detached piece of the dry film in the platingsolution or a growth of an undesired post electrode can be prevented.Moreover, by forming the slits in a grid pattern on the second dry film,a wafer warpage due to the internal stress of the dry film can beprevented and a problem in a workflow can be prevented.

<<4>> One Aspect of Present Invention

A method of manufacturing a device with pillar-shaped components will bedescribed below. A detail of this method is described in the firstembodiment. In one aspect of the present invention, a method ofmanufacturing a device with pillar-shaped components, comprises:

attaching a first photoresist dry film to a substrate; forming firstholes penetrating the first photoresist dry film in a thicknessdirection of the first photoresist dry film;

forming first pillar-shaped parts in the first holes by plating;thereafter attaching a second photoresist dry film to an upper surfaceof the first photoresist dry film, thereby forming a multilayeredstructure of photoresist dry films;

forming second holes penetrating the second photoresist dry film in athickness direction of the second photoresist dry film so as to beconnected with said the first holes respectively; and

forming second pillar-shaped parts on the first pillar-shaped parts byplating;

wherein said forming of the first pillar-shaped parts is performed sothat upper surfaces of the first pillar-shaped parts are lower than theupper surface of the first photoresist dry film.

In the method, it is preferable that said forming of the secondpillar-shaped parts be performed so that upper surfaces of the secondpillar-shaped parts are higher than an upper surface of the second photoresist dry film.

In the method, it is preferable that said forming of the secondpillar-shaped parts be performed so that the upper surfaces of thesecond pillar-shaped parts are higher than an upper surface of thesecond photoresist dry film.

The method may further comprise:

removing the second photoresist dry film and the first photoresist dryfilm;

mounting an additional component on the substrate;

sealing the additional component and the pillar-shaped componentscomposed of the first and second pillar-shaped parts with a moldingresin, thereby forming a sealed structural body; and

applying chemical mechanical polishing to the sealed structural body.

In the above method, after said applying of chemical mechanicalpolishing, a length of the second pillar-shaped parts is greater than alength of the first pillar-shaped parts.

In the above method, said forming of the first pillar-shaped parts mayperformed repeatedly a plurality of times so as to form a multilayeredstructure of the first photoresist dry films, and thereafter saidforming of the second pillar-shaped parts is performed.

In the above method, said forming of the first holes is a step offorming a plurality of first holes, and said forming of the firstpillar-shaped parts is a step of forming a plurality of firstpillar-shaped parts at a same process so that any of upper surfaces ofthe first pillar-shaped parts are lower than the upper surface of thefirst photoresist dry film.

In the above method, said forming of the second holes is a step offorming a plurality of second holes, and said forming of the secondpillar-shaped parts is a step of forming a plurality of secondpillar-shaped parts at a same process so that any of upper surfaces ofthe second pillar-shaped parts are lower than the upper surface of thefirst photoresist dry film.

In the above method, the pillar-shaped components may be post electrodesor pillar-shaped metal components for radiating heat. Further, in theabove method, the substrate may be a semiconductor substrate.

<<5>> Another Aspect of Present Invention

A method of manufacturing a device with pillar-shaped components will bedescribed below. A detail of this method is described in the firstembodiment. In another aspect of the present invention, a method ofmanufacturing the device with pillar-shaped components, comprises:

attaching a plurality of photoresist dry films in layers to a substrateso as to form a multilayered structure of the photoresist dry films onthe substrate;

forming holes penetrating the multilayered structure of the photoresistdry films in a thickness direction of the multilayered structure;

forming the pillar-shaped components in the holes by plating; and

forming a slit on layer of the multilayered structure of the photoresistdry films.

In the above method, said forming of the pillar-shaped componentsincludes:

attaching a first photoresist dry film of the multilayered structure ofthe photoresist dry films to the substrate;

forming first holes penetrating the first photoresist dry film in athickness direction of the first photoresist dry film;

forming first pillar-shaped parts as parts of the pillar-shapedcomponents in the first holes by plating;

attaching a second photoresist dry film of the multilayered structure ofthe photoresist dry films to an upper surface of the first photoresistdry film;

forming second holes penetrating the second photoresist dry film in athickness direction of the second photoresist dry film so that thesecond holes are connected to the first holes respectively; and

forming second pillar-shaped parts as parts of the pillar-shapedcomponents on the first pillar-shaped parts respectively by plating.

In the above method, it is preferable that said forming of the firstpillar-shaped parts be performed so that upper surfaces of the firstpillar-shaped parts are lower than the upper surface of the firstphotoresist dry film.

In the above method, it is preferable that said forming of the firstpillar-shaped parts be performed repeatedly a plurality of times so asto form a multilayered structure of the first pillar-shaped parts, and

thereafter said forming of the second pillar-shaped parts is performed.

In the above method, said forming of the slit is performed on a firstphotoresist dry film which is a photoresist dry film attached to thesubstrate, out of the multilayered structure of the photoresist dryfilms.

In the above method, said forming of the slits is performed on a secondphotoresist dry film which is the second film counted from a side of thesubstrate in the multilayered structure of the photoresist dry films.

In the above method, the slit includes a plurality of first lineargrooves extending in a first direction, and a plurality of second lineargrooves extending in a second direction perpendicular to the firstdirection.

The method may further comprise:

removing the plurality of photoresist dry films;

mounting an additional component on the substrate or a wiring layerdisposed on the substrate;

sealing the additional component and the pillar-shaped components with amolding resin, thereby forming a sealed structural body; and

applying chemical mechanical polishing to the sealed structural body.

The method may comprise: removing a predetermined width of photoresistdry film selected from the multilayered structure of the photoresist dryfilms on a wafer edge side.

In the above method, said removing of the predetermined width ofphotoresist dry film is a step of removing a predetermined width of thesecond photoresist dry film or another photoresist dry film disposedabove the second photoresist dry film.

In the above method, said removing of the predetermined width ofphotoresist dry film is a step of removing the first dry film, and

the method may further comprise: forming a coating layer to cover aregion where the predetermined width of the first dry film is removed.

In the above method, said removing of the predetermined width ofphotoresist dry film is a step of removing the first dry film, and thepredetermined width of the first dry film on the wafer edge side iscovered by the second photoresist dry film or another photoresist dryfilm disposed above the second photoresist dry film.

The method may further comprise: forming a coating layer on a bottompart of the slit.

In further aspect of the present invention, a method of manufacturingthe device with pillar-shaped components, comprises:

attaching a first photoresist dry film to a substrate;

attaching a second photoresist dry film to the first photoresist dryfilm;

forming holes penetrating the first and second photoresist dry films ina thickness direction of the first and second photoresist dry films; and

forming pillar-shaped components in the holes by plating;

wherein:

a whole region above the substrate includes a first region where thepillar-shaped components are formed on any of the first and secondphotoresist dry films by plating and a second region where nopillar-shaped components are formed on any of the first and secondphotoresist dry films, and

said forming of the holes is performed in both of the first and secondregions.

In the above method, the pillar-shaped components may be post electrodesor pillar-shaped metal components for radiating heat. Further, in theabove method, the substrate may be a semiconductor substrate.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of following claims.

What is claimed is:
 1. A method of manufacturing a device withpillar-shaped components, comprising: attaching a first photoresist dryfilm to a substrate; forming first holes penetrating the firstphotoresist dry film in a thickness direction of the first photoresistdry film; forming first pillar-shaped parts in the first holes byplating; thereafter attaching a second photoresist dry film to an uppersurface of the first photoresist dry film, thereby forming amultilayered structure of photoresist dry films; forming second holespenetrating the second photoresist dry film in a thickness direction ofthe second photoresist dry film so as to be connected with the firstholes respectively; forming second pillar-shaped parts on the firstpillar-shaped parts by plating, wherein said forming the firstpillar-shaped parts is performed so that upper surfaces of the firstpillar-shaped parts are lower than the upper surface of the firstphotoresist dry film; removing the second photoresist dry film and thefirst photoresist dry film; mounting an additional component over thesubstrate; sealing the additional component and the pillar-shapedcomponents composed of the first and second pillar-shaped parts with amolding resin, thereby forming a sealed structural body; and applyingchemical mechanical polishing to the sealed structural body.
 2. Themethod according to claim 1, wherein said forming the secondpillar-shaped parts is performed so that upper surfaces of the secondpillar-shaped parts are higher than an upper surface of the secondphotoresist dry film.
 3. The method according to claim 1, wherein aftersaid applying chemical mechanical polishing, a length of the secondpillar-shaped parts is greater than a length of the first pillar-shapedparts.
 4. The method according to claim 1, wherein said forming thefirst pillar-shaped parts is performed repeatedly a plurality of timesso as to form a multilayered structure of the first photoresist dryfilms, and thereafter said forming the second pillar-shaped parts isperformed.
 5. The method according to claim 1, wherein said forming thefirst holes comprises forming a plurality of first holes, and saidforming the first pillar-shaped parts comprises forming a plurality offirst pillar-shaped parts during a same process so that any of the uppersurfaces of the first pillar-shaped parts are lower than the uppersurface of the first photoresist dry film.
 6. The method according toclaim 5, wherein said forming the second holes comprises forming aplurality of second holes, and said forming the second pillar-shapedparts comprises forming a plurality of second pillar-shaped parts duringa same process so that any of upper surfaces of the second pillar-shapedparts are lower than the upper surface of the second photoresist dryfilm.